That Travel & Leisure survey this supposed "fact" is based on is flawed in the extreme. Right behind Philly in the "ugly" sweepstakes were Washington DC and Dallas. I live in the latter and, say what you want about the place, there are a ton of good-looking people here.
Sure, Philly has its problems (what big American city doesn't?)but it's full of history, great architecture, good museums, and interesting neighborhoods.
These "best cities" lists are good for a laugh but not much stock should be put into them. They're entirely subjective and few readers/respondents have been to each city on the list and know it well enough to make comparisons. They might know the airport, the hotel/convention center, a couple of restaurants/tourist spots and that's it.
Of course, Miami was deemed to have the most attractive people. And that I won't argue with